The radio waves transmitted by a wireless communication device during communications may expose the user to measurable radio frequency (RF) radiation. When a user uses a mobile terminal such as a mobile phone to make a call, the head of the user is always within the electromagnetic radiation field emitted by the mobile phone. Therefore, many countries including the People's Republic of China have issued complete and safe standards and specifications to manage and restrict the problem of exposure of RF energy. Here, the specific absorption rate (SAR) is an important evaluation parameter, which refers to the electromagnetic wave energy absorption rate of mobile phones or wireless communication products. Popularly, SAR is used to measure whether the influence of mobile phone radiation upon the body of a user, especially, the head of the user conforms to the relevant standards. SAR is also a unit for measuring the amount of RF energy absorbed by the body when using a mobile phone, and is used as a criterion for body protection.
Presently, mobile terminals have been designed for use in such very rigid limitations, so various devices and methods are being developed to reduce the SAR, for example, materials for absorbing electromagnetic waves are added to mobile terminals, or metal parts are arranged properly to optimize the RF-induced current, complicated antenna design is used to reduce the SAR, and so on. However, these design methods are easily affected by the type of mobile terminals, so they do not have universal applicability.
Therefore, there is a need to improve and develop the prior art.